A retired Pennsylvania state trooper killed a turnpike toll collector and a security guard in a holdup attempt at a toll plaza and then was shot dead by troopers while trying to escape with the money, authorities said.

Clarence Briggs, who retired four years ago, confronted two Pennsylvania Turnpike toll collectors with a handgun on Sunday morning at the Fort Littleton toll plaza in Dublin Township, 65 miles west of Harrisburg, the state capital, police said. Briggs ordered both into an adjoining office and tried to tie them up but fled after a struggle, they said. Both employees left the building as a fare collection vehicle arrived and a security guard emerged, they said, reports the Associated Press .

Briggs then shot and killed one of the toll collectors, Danny Crouse, who had been on the job for less than three months, and Ronald Heist, a retired York police officer who was employed by a detective agency and was working as turnpike security, Capt. David Cain said.

Briggs then fired at the fare collection vehicle, Cain said, and after the driver fled he jumped into the vehicle and drove it to his car, which was parked at the end of a service ramp a few hundred yards away. He started unloading money from the collection vehicle, Cain said.

Troopers arrived within minutes, and the first trooper exchanged shots with Briggs, who was wounded and died at the scene, police said.